Sankyaku kenzan Ao no Yajuu? Moujuu? ...Chinjuu? Naruto : Season 1 Episode 161

As Gai and Lee leave Konoha on a mission, two strangers disguise themselves as them and sneak into the village to learn its secrets. Tsunade, Sakura and Tenten have big plans in store for these impostors, plans that'll make their lives miserable.